Energy reclamation from air-moving systems

ABSTRACT

A data center includes a computing room, computing devices in the computing room, an air handling system, and a turbine system. Air moved by the air handling system flows across heat producing components in the computing devices in the computing room. A rotor of the turbine system rotates in response to at least a portion of the air moved by the air handling system. The turbine system generates electricity from rotation of the rotor.

BACKGROUND

Organizations such as on-line retailers, Internet service providers,search providers, financial institutions, universities, and othercomputing-intensive organizations often conduct computer operations fromlarge scale computing facilities. Such computing facilities house andaccommodate a large amount of server, network, and computer equipment toprocess, store, and exchange data as needed to carry out anorganization's operations. Typically, a computer room of a computingfacility includes many server racks. Each server rack, in turn, includesmany servers and associated computer equipment.

Because a computing facility may contain a large number of servers, alarge amount of electrical power may be required to operate thefacility. In addition, the electrical power is distributed to a largenumber of locations spread throughout the computer room (e.g., manyracks spaced from one another, and many servers in each rack). Usually,a facility receives a power feed at a relatively high voltage. Thispower feed is stepped down to a lower voltage (e.g., 110V). A network ofcabling, bus bars, power connectors, and power distribution units, isused to deliver the power at the lower voltage to numerous specificcomponents in the facility.

Computer systems typically include a number of components that generatewaste heat. Such components include printed circuit boards, mass storagedevices, power supplies, and processors. For example, some computerswith multiple processors may generate 250 watts of waste heat. Someknown computer systems include a plurality of such larger,multiple-processor computers that are configured into rack-mountedcomponents, and then are subsequently positioned within a rackingsystem. Some known racking systems include 40 such rack-mountedcomponents and such racking systems will therefore generate as much as10 kilowatts of waste heat. Moreover, some known data centers include aplurality of such racking systems. Some known data centers includemethods and apparatus that facilitate waste heat removal from aplurality of racking systems, typically by circulating air through oneor more of the rack systems.

Many data centers rely on forced air systems and air conditioning tomaintain the temperatures and other environmental conditions in the datacenter within acceptable limits. The initial and ongoing costs ofinstalling and operating these systems may add substantial cost andcomplexity to data center operations. In addition, in many data centers,the forced air systems and air conditioning may be relativelyinefficient in that a substantial amount of energy is wasted (forexample, dissipated to the surroundings in the form of heat and exhaustflow kinetic energy.)

Data centers often include components and systems to provide back-uppower to servers in the event of a failure of components or systems in aprimary power system. Providing full redundancy of electrical power fora data center may, however, be costly both in terms of capital costs (inthat in may require a large number of expensive switchboard, UPSs, andPDUs, for example) and in terms of costs of operation and maintenance.In addition, some data centers do not provide redundant power for allcooling systems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating one embodiment of a data centerincluding a turbine system for reclaiming energy from moving air.

FIG. 2 illustrates one embodiment of an energy recovery system with aturbine system having a stator ring.

FIG. 3 illustrates a turbine system at a horizontal exhaust vent of adata center.

FIG. 4 illustrates a turbine system including a mechanism for adjustingthe orientation of a rotor.

FIG. 5 is a top view of a data center illustrating adjustment of theorientation of a turbine about a vertical axis.

FIG. 6 illustrates one embodiment of a turbine system in an air flowpassage in air handling system.

FIG. 7 illustrates one embodiment of a data center having turbinesystems for recovering energy from moving air in the data center.

FIG. 8 illustrates one embodiment of an energy recovery system installedon a cooling tower.

FIG. 9 illustrates use of a turbine system to reclaim energy from airmoving in a space.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Itshould be understood, however, that the drawings and detaileddescription thereto are not intended to limit the invention to theparticular form disclosed, but on the contrary, the intention is tocover all modifications, equivalents and alternatives falling within thespirit and scope of the present invention as defined by the appendedclaims. The headings used herein are for organizational purposes onlyand are not meant to be used to limit the scope of the description orthe claims. As used throughout this application, the word “may” is usedin a permissive sense (i.e., meaning having the potential to), ratherthan the mandatory sense (i.e., meaning must). Similarly, the words“include,” “including,” and “includes” mean including, but not limitedto.

DETAILED DESCRIPTION OF EMBODIMENTS

Systems and methods for reclaiming or recovering energy from moving airare disclosed. According to one embodiment, a data center includes acomputing room, computing devices in the computing room, an air handlingsystem, and a turbine system. Air moved by the air handling system flowsacross heat producing components in the computing devices in thecomputing room. A rotor of the turbine system rotates in response to atleast a portion of the air moved by the air handling system. The turbinesystem generates electricity from rotation of the rotor.

According to one embodiment, a system includes one or more rooms and anair handling system that moves air through the rooms. A rotor of theturbine system rotates in response to air moved by the air handlingsystem. The turbine system generates electricity from rotation of therotor.

According to one embodiment, air is moved through an enclosed space tocontrol conditions of the air in the enclosed space. At least a portionof the air is moved a through a rotor of a turbine system such that arotor of the turbine system rotates. Electrical power is generated fromthe rotation of the rotor.

As used herein, “air handling system” means a system that provides ormoves air to, or removes air from, one or more systems or components.

As used herein, “duct” means a tube, channel, pipe, or fluid carrierthat can direct or channel a gas, such as air, from one location toanother. A duct may have any cross section, including square,rectangular, circular, ovate, or irregular. A duct may have a uniformcross sectional area over its length or a varying cross sectional areaover its length. A duct may, for example, include a converging sectionin which the cross sectional area of the duct decreases, a divergingsection in which the cross sectional area of the duct increases, orboth.

As used herein, “exhaust” means air that is being exhausted or expelledfrom an air handling system (for example, to outside air).

As used herein, a “turbine” means a device or system that producesrotary motion from a moving fluid. Examples of turbine types include ablade turbine, helix turbine, bladeless turbine, and statorless turbine.A turbine may be shrouded or unshrouded.

As used herein, a “turbine system” means a system that includes one ormore turbines.

As used herein, a “rotor” means a rotating part of a device or system.

As used herein, “infrastructure” means systems, components, or elementsof a system that provide resources for a computing device, such aselectrical power, data exchange capability with external systems, air,heat removal, and environmental control (for example, humidity control,particulate control).

As used herein, an “aisle” means a space next to one or more racks.

As used herein, “air moving device” includes any device, element,system, or combination thereof that can move air. Examples of air movingdevices include fans, blowers, and compressed air systems.

As used herein, “ambient” refers to a condition of outside air at thelocation of a system or data center. An ambient temperature may betaken, for example, at or near an intake hood of an air handling system.

As used herein, a “cold aisle” means an aisle from which air can bedrawn for use in removing heat from a system, such as a rack computingsystem.

As used herein, “computing” includes any operations that can beperformed by a computer, such as computation, data storage, dataretrieval, or communications.

As used herein, “computing device” includes any of various devices inwhich computing operations can be carried out, such as computer systemsor components thereof. One example of a computing device is arack-mounted server. As used herein, the term computing device is notlimited to just those integrated circuits referred to in the art as acomputer, but broadly refers to a processor, a server, amicrocontroller, a microcomputer, a programmable logic controller (PLC),an application specific integrated circuit, and other programmablecircuits, and these terms are used interchangeably herein. Some examplesof computing devices include e-commerce servers, network devices,telecommunications equipment, medical equipment, electrical powermanagement and control devices, and professional audio equipment(digital, analog, or combinations thereof). In various embodiments,memory may include, but is not limited to, a computer-readable medium,such as a random access memory (RAM). Alternatively, a compact disc-readonly memory (CD-ROM), a magneto-optical disk (MOD), and/or a digitalversatile disc (DVD) may also be used. Also, additional input channelsmay include computer peripherals associated with an operator interfacesuch as a mouse and a keyboard. Alternatively, other computerperipherals may also be used that may include, for example, a scanner.Furthermore, in the some embodiments, additional output channels mayinclude an operator interface monitor and/or a printer.

As used herein, “data center” includes any facility or portion of afacility in which computer operations are carried out. A data center mayinclude servers dedicated to specific functions or serving multiplefunctions. Examples of computer operations include informationprocessing, communications, simulations, and operational control.

As used herein, a “free cooling” includes a mode of operation in whichan air handling sub-system pulls air at least partially from an externalsource (such as air outside a facility) and forces the air to electronicequipment without active chilling in the air-handling sub-system (e.g.,fluid flow through the chiller coils in the air handling sub-system isshut off by closing a flow control valve).

As used herein, a “hot aisle” means an aisle into which heated air canbe discharged for use in removing heat from a system, such as a rackcomputing system.

As used herein, “mechanical cooling” means cooling of air by a processthat involves doing mechanical work on at least one fluid, such asoccurs in vapor-compression refrigeration systems.

As used herein, a “module” is a component or a combination of componentsphysically coupled to one another. A module may include functionalelements and systems, such as computer systems, circuit boards, racks,blowers, ducts, and power distribution units, as well as structuralelements, such a base, frame, housing, or container.

As used herein, “rack computing systems” means a computing system thatincludes one or more computing devices mounted in a rack.

As used herein, “reserve power” means power that can be supplied to anelectrical load upon the failure of, or as a substitute for, primarypower to the load.

As used herein, “room” means a room or a space of a building. As usedherein, “computer room” means a room of a building in which computingdevices, such as rack-mounted servers, are operated.

As used herein, a “space” means a space, area or volume.

In various embodiments, a system includes a turbine system thatgenerates electricity from air moved by an air handling system. FIG. 1is a block diagram illustrating one embodiment of a data centerincluding a turbine system for reclaiming energy from moving air.Cooling system 400 may remove heat from data center 402. In theembodiment illustrated in FIG. 1, cooling system 400 includes airhandling sub-systems 404. Air handling sub-systems 404 may providecooling air to data center 402.

For illustrative purposes, only one air handling sub-system 404 is shownin FIG. 1. The number of air handling sub-systems 404 in cooling system400 may vary, however. In some embodiments, cooling system 400 includesmany air handling sub-systems 404. In facilities with multiple airhandling sub-systems and/or multiple data centers, cross-over ducts maybe provided (e.g., on the supply side, the return side, or both) toallow cooling air from air handling sub-systems to be distributed and/orredirected within a data center or among data centers. Air handlingsub-systems may be commonly controlled, separately controlled, or acombination thereof. In certain embodiments, only a sub-set of the totalair handling sub-systems for a data center is provided with outside airvents. For example, half the air handling systems at a data center mayhave both outside air vents and return air vents, while the other halfthe air handling systems at a data center have only return air vents.

Each air handling sub-system 404 may be coupled to data center 402 bysupply duct 408 and return duct 410. Cooling air may flow from airhandling sub-system 404 through supply duct 408 into plenum 412. Fromplenum 412, cooling air may pass through flow restriction devices 414into room 416. Cooling air may pass over racks 418. After the air isheated by racks 418, the air may pass through return duct 410. Air maybe recirculated through one or more air handling sub-systems ordischarged from the system through exhaust vent 420. Exhaust vent 420includes exhaust damper 422.

Air handling sub-system 404 includes fan 430, humidifier 432, filter434, return air vent 436, return air damper 438, outside air vent 440,and outside air damper 442. Fan 430 is coupled to VFD 444. VFD 444 iscoupled to control unit 450. Control of fan 430 may be, for example, asdescribed above relative to FIG. 1. Return air vent 438 may receive airreturning from data center 102 through return duct 410. Outside air vent440 may receive outside air.

Cooling system 400 includes chilled water subsystems 452. Chilled watersubsystems 452 may be coupled in heat transfer communication with airhandling sub-systems 404. Chilled water sub-system 452 includes coils454 and valve 456. Valve 456 is coupled to control unit 450. Valve 456may be opened and closed by signals from control unit 450. The positionof valve 456 may be used to regulate the use of chilled water to coolair in air handling sub-system 404. In one embodiment, a common chilledwater subsystem 452 provides chilled water to two more of air handlingsub-systems 404. In certain embodiments, each air handling sub-system404 is cooled by a dedicated chilled water subsystem 452.

In some embodiments, chilled water subsystems 452 are coupled to achilled water heat removal system. Examples of chilled water heatremoval systems include a service water subsystem, air-conditionsrefrigerant sub-system, or a cooling tower sub-system.

Control unit 450 may be programmed to control devices in handlingsub-systems 404 and/or chilled water sub-systems 452. Control unit 450is coupled to fan 430, humidifier 432, return air damper 438, outsideair damper 442, and exhaust damper 422. Control unit 450 is in datacommunication with temperature sensors, pressure sensors, or both. Inone embodiment, all of air handling sub-systems 404 and chilled-watersub-systems are controlled with a common control unit (e.g., controlunit 450). In other embodiments, separate controllers are provided foreach air handling sub-system 404 and chilled water sub-systems 452, orfor a subset of the air handling sub-systems 404 and/or chilled watersub-systems 452. Devices in air handling sub-systems 404 and chilledwater sub-systems 452 may be controlled automatically, manually, or acombination thereof.

In the embodiment shown in FIG. 1, air handling sub-system 404 may forceair through supply duct 408 into plenum 412. In other embodiments,cooling air may be forced directly into room 416 through a supply ductwithout going through a plenum. In various embodiments, flow restrictiondevices 414 may be chosen to control the flow rates and distribution ofcooling air among various racks 418 in room 416.

In certain embodiments, a control unit includes at least oneprogrammable logic controller. The PLC may, among other things, regulateair moving devices and open and close valves or dampers in cooling airsystems based upon command signals from an operator to move air flowthrough a data center as necessary for the prevailing operationalconditions. Alternatively, the PLC may modulate valves and dampersbetween fully open and fully closed positions to modulate airflow.

A control system may include temperature measurement devices that are,in one embodiment, thermocouples. Alternatively, the temperaturemeasurement devices include, but are not limited to, resistancetemperature detectors (RTDs) and any device that facilitate coolingoperation as described herein. For example, a thermocouple may bepositioned within mixing plenum to facilitate measuring a temperature ofthe air the mixing plenum.

In various embodiments, operation of one or more air handling systemsmay be controlled in response to one or more conditions. For example,control system 128 may be programmed to increase the speed of some orall of air moving devices when one or more predetermined conditions aremet, such as temperature and humidity.

In various embodiments, operation of one or more air handlingsub-systems of a cooling system may be controlled in response to one ormore conditions. For example, the controller may be programmed to switchthe air source for an air-handling sub-system from return air to outsideair when one or more predetermined conditions are met, such astemperature and humidity.

Cooling system 400 includes turbine system 470. Turbine system 470includes turbine 472, generator unit 474, and energy storage system 476.Turbine 472 is installed in duct 478. Turbine 472 includes rotor 480 andturbine housing 482. Rotor 480 includes blades 484. Rotor 480 may iscoupled to rotation on housing 482. Rotor 480 may rotate in response toair passing through duct 478.

Generator unit 474 includes generator 490 and turbine system controller492. Generator 490 is coupled to turbine 472 by way of drive system 494.Drive system 494 may include elements that link an output shaft of rotor480 to an input shaft in generator 490. Elements linking a rotor to agenerator may include, for example, one or more sheaves coupled to oneanother by way a belt or chain.

In some embodiments, elements of drive system 494 are selected tocontrol a ratio for rotation of a rotor shaft relative to a generatorshaft. For example, a sheave and belt system may be used to establish a10:1 ratio between an input shaft of generator 490 and an output shaftof rotor 480. In certain embodiments, a turbine system includes agearbox for controlling a ratio between rotation of a rotor and agenerator shaft.

In some embodiments, turbine system 470 is operated to generateelectricity from air being expelled from cooling system. For example,when exhaust dampers 422 are open, a portion of the air moving throughcooling system 400 may be exhausted to the outside via duct 478. As airflows through duct 478, rotor 480 may turn within in housing 482.Rotation of rotor 480 may drive generator 490 to product electricity.Energy from the electricity may be stored in energy storage device 476.

In some embodiments, turbine system controller 492 controls operation ofturbine system 470 to generate electricity from moving air in coolingsystem 400. In one embodiment, turbine system controller 492 includes aprogrammable logic controller. Turbine system controller 492 maycontrol, for example, whether turbine system 470 is on or off, a rate ofcharging of energy storage device, or a gear ratio between rotor 480 andan input shaft of generator 490.

In some embodiments, electrical energy generated from a turbine coupledto a cooling air system is used to provide electrical power foroperating components of the cooling system. For example, electricalenergy storage device 476 may be used to supply power to controller 450,air moving device 430, or components of chilled water sub-system 452. Insome embodiments, electrical energy storage device 476 serves as aback-up electrical power system for cooling system 400. In oneembodiment, electrical energy storage device 476 is part of anuninterruptible power supply.

In some embodiments, air flow to a turbine is controlled to promoteelectricity generation. In one embodiment, air is channeled through apassage having a decreasing cross sectional area such that the velocityof air is higher when it passes through a turbine. For example, duct 478converges to neck 479. The intake of turbine is at a reduced crosssection part of duct 478, in this case, neck 479. The velocity of airflowing through duct 478 at neck 479 is higher than the velocity of theair entering exhaust vent 420.

FIG. 2 illustrates one embodiment of an energy recovery system with aturbine system having a stator ring. System 500 includes turbine system502. Turbine system 502 receives air flow that is exiting system an airhandling system through exhaust duct 420. The air handling system may besimilar to that described above relative to FIG. 1.

Turbine system 502 includes turbine 504 and turbine control unit 506.Turbine 504 includes rotor 510 and stator ring 512. Rotor 510 includesblades 514 and magnetic elements 516. Turbine control unit 506 includescontrol unit 517 and energy storage device 518. Energy storage device518 may be an uninterruptible power supply.

As rotor 510 spins in response to air moving through turbine 504, motionof magnetic elements 516 relative to stator ring 512 may induceelectrical current in stator ring 512. Energy generated by turbine 504may be stored in energy storage device 518.

In some embodiments, a turbine system rotates in response to ahorizontal air flow. FIG. 3 illustrates a turbine system at a horizontalexhaust vent of a data center. Data center 520 includes building 522.Exhaust plenum 524 of an air handling system in located on roof 526 ofbuilding 522. Air from the air handling system is expelled through duct527. Turbine system 528 includes rotor 530, stator ring 532, and turbinecontrol unit 534.

Rotor 530 may rotate in response to air flow through duct 527. Rotationof rotor 530 may generate electricity. The electricity may be stored in,for example, an energy storage device such as an uninterruptible powersupply. The stored energy may be used to supply electrical power forsystems in data center 520.

In some embodiments, a turbine system includes a mechanism for adjustingan orientation of its rotor. FIG. 4 illustrates a turbine systemincluding a mechanism for adjusting the orientation of a rotor. Datacenter 540 includes air handling system 542 and turbine system 544. Airfrom air handling system 542 may be expelled through duct 420.

Turbine system 544 includes orientation mechanism 548 and turbine systemcontrol unit 550. Turbine system control unit 550 includes controller552 and energy storage device 554. Orientation mechanism 548 may amotorized drive mechanism. Controller 552 may be operated to control theorientation of turbine 504. In certain embodiments, orientation of aturbine is controlled manually.

A turbine system mounting system may allow for orientation in anydirection. In some embodiments, a turbine is mounted on a system thatallows rotation in any axis, such as an eyeball mount. In certainembodiments, an orientation mechanism can adjust orientation of aturbine in two axes (for example, a pitch axis and a yaw axis relativeto the direction of air flow).

In some embodiments, a turbine is oriented to increase rotation of itsrotor (and thus the amount of electricity that can be generated). Forexample, a rotor may be tilted such that the axis of the rotor is betteraligned with the direction of air flow. Position 555 shows an example ofturbine 504 in a tilted orientation.

In some embodiments, a turbine is adjustable between a position or anorientation that enables electrical energy generation from air moved byan air handling system or an outdoor wind. For example, orientationmechanism 548 may be operated to adjust turbine 504 to position 556. Inposition 556, turbine 504 may generate electrical energy from windblowing through turbine 504.

In some embodiments, turbine 504 is adjustable about a vertical axiswhen turbine 504 is in raised position 556. FIG. 5 is a top view of adata center illustrating adjustment of the orientation of a turbineabout a vertical axis. If the wind is blowing the direction of thearrows, turbine 504 may adjusted from position 556 a to position 556 b.

In some embodiments, a turbine is located in an air passage in an airhandling system. The air passage may be part of a closed loop, such as arecirculation duct. FIG. 6 illustrates one embodiment of a turbinesystem in an air flow passage in air handling system. System 580includes air handling system 402 and turbine system 582. Turbine system582 includes turbine 584 in air passage 586. Air passage 586 may aportion of return duct 410, or a tube residing in return duct 410. Insome embodiments, recirculation duct includes dampers that allow airexiting computer room 416 to be channeled through passage 586, to abypass passage, or a combination thereof.

A rotor of turbine 584 may rotate in response to air flowing throughreturn duct 410. Generator 490 may be operated to produce electricityfrom rotation of the rotor.

FIG. 7 illustrates one embodiment of a data center having turbinesystems for recovering energy from moving air in the data center. Datacenter 600 includes room 601, rack computing systems 602, air handlingsystem 604, and electrical power system 605. Each of rack computingsystems 602 includes rack 606 and computing devices 608. Computingdevices 608 may be mounted in racks 606. Racks 606 may include vents onfront sides 610 of racks 606 and back sides 612 of racks 606. Vents inthe racks may allow air flow through in either direction through theinterior of racks 606, and through computing devices 608 held in racks606.

Each of rack computing systems 602 may be positioned next to one ofchambers 614. Each of chambers 614 may partially contain air exitingfrom racks 604 and segregate the air exiting the racks from other air inroom 601. Chambers 614 may serve as a hot aisle for one of rackcomputing systems 602. Spaces in front of racks 606 may serve as coldaisles for rack computing systems 602.

Air handling system 604 includes air removal systems 620, intake vents622, and control system 628. Each of air removal systems 620 includesair moving devices 630, duct 632, and exhaust roof vent 634. Although inFIG. 1 only one symbol is shown to represent air moving devices 630 foreach air removal system, each of air removal systems 620 may include anynumber of air moving devices. In some embodiments, air moving devicesare arranged in a row above a hot aisle, such as the hot aisle providedin chamber 614 of data center 600.

Air moving devices 630 may be operated to create negative pressure inchambers 614 relative to the air at the inlet openings in racks 606. Inthe system shown in FIG. 6, the air pressure at the inlets may match theambient air pressure in room 601. The negative pressure in chambers 614may draw air through racks 606 and through computing devices 608installed in racks 606. Air moving devices 630 may pull heated air fromthe hot aisles and force the heated air through ducts 632.

Some or all of air removal systems 620 may include recirculation plenum636. Recirculation plenum 636 may receive some of the air dischargedinto ducts 632. Recirculation plenum 636 may vent some air into room601. Recirculated air from recirculation plenum 636 may mix with outsideair introduced through intake vents 622. In some embodiments, airrecirculated from an air removal system (such as air removal systems620) is combined with outside air in a mixing plenum.

Control system 628 may be coupled to air moving devices 630 (in FIG. 1,control system 628 is shown connected to only one of air moving devices630 for clarity) by way of variable frequency drives (VFDs) 640. Each ofVFDs 640 may receive control signals from control system 628 andsubsequently modulate a rotational velocity of a fan in one of airmoving devices 630. In certain embodiments, an outside air damper,return air damper, exhaust damper, or combinations thereof, aremodulated via a control system to modulate air flow.

Data center 600 includes energy recovery system 650. Energy recoverysystem 650 includes energy recovery control unit 652, exhaust ductturbine system 654, intake duct turbine system 655, hot aisle turbinesystem 656, energy storage device 658, and flow control mechanism 660.Intake duct turbine system 655 may be similar to turbine systemsdescribed above relative to FIGS. 1 and 2.

Exhaust duct turbine system 654 and hot aisle turbine system 656 eachinclude rotors 661 and generators 662. Rotor 661 of exhaust duct turbinesystem 654 may rotate in response to air flow through duct 632. Rotor661 of exhaust duct turbine system 656 may rotate in response to airflow through hot aisle 612. Generators 662 may generate electricity fromrotation of rotors 661. Electricity generated by generators 662 may bestored in energy storage device 658. Energy stored in electrical energystorage device 658 may be used to supply electrical power to componentsin data center 600, such as air handling system 604.

In some embodiments, turbine system 654 and turbine system 656 includehelical rotors. In various embodiments, the shaft of the helical rotorsmay be oriented in-line with the direction of flow, perpendicular to thedirection of flow, or any other suitable angle.

Flow control mechanism 660 is coupled to energy recovery control unit652. Flow control mechanism 660 includes movable vanes 33 670. Flowcontrol mechanism 660 may be controlled by energy recovery control unit652 to alter flow to the rotors of turbine system 654. For example, flowcontrol mechanism 660 may be operated to divert air flow to turbinesystem 654, reduce the effective cross sectional area of duct 632 toincrease air velocity at the inlet of turbine system 654, or both.

In some embodiments, energy recovery control unit 652 operates flowcontrol mechanism 660 to optimize generation of electricity by turbinesystem 654. As an example, energy recovery control unit 652 may operateflow control mechanism 660 to vary the flow of air to turbine system 654based on a flow rate through duct 632. In certain embodiments, energyrecovery control unit 652 operates flow control mechanism 660 to varythe flow to turbine system 654 based on a variable frequency drive foran air moving device generating air flow to a turbine system. In oneembodiment, flow control mechanism 660 may be operated based on thefrequency of a variable frequency drive for air moving device 630 movingair across turbine system 654. For example, if the operating frequencyof variable frequency drive is reduced from 60 Hz to 30 Hz, flow controlmechanism 660 may be operated to reduce the effective cross sectionalarea at the inlet of turbine system 654 to maintain velocity of airflowto turbine system 654.

FIG. 8 illustrates one embodiment of an energy recovery system installedon a cooling tower. The cooling tower may be part of a cooling systemfor a data center or building, such as cooling system 400 describedabove relative to FIG. 1. Cooling tower 680 includes fan 682. Fan 682may draw air through evaporator section 683 and expel the air into duct684.

Energy recovery system 686 includes turbine 688 and energy storagedevice 690. Turbine 688 may generate electricity in response to airflowing through turbine 688. Energy generated in turbine 688 may bestored in energy storage device 690.

FIG. 9 illustrates energy reclamation from air moving in a space using aturbine system. At 700, air is moved through an enclosed space tocontrol conditions of the air in the enclosed space. The enclosed spacemay be, for example, a computing room of a data center. The air may beused to remove heat from heat producing components in the room.

At 702, air is moved through a rotor of a turbine system such that arotor of the turbine system rotates. In some embodiments, the rotor ofthe turbine system is at or near an exhaust of an air handling system tooutside air. In some embodiments, the rotor of the turbine system is inan air passage (for example, a return air duct) of an air handlingsystem. In certain embodiments, the orientation of the rotor is adjustedto increase rotation (for example, aligning the axis of the rotor withthe direction of air flow.

At 704, electricity is generated from rotation of the rotor. In someembodiments, the energy produced is stored in a back-up power supplysystem, such as a UPS. The stored energy may be used to supply power toelectrical systems. In certain embodiments, the stored energy is used asa back-up power source for a cooling system.

In some embodiments, a data center includes an air removal system thatcreates a negative pressure in a hot aisle to pull air through computingdevices in the data center. In some embodiments, a data center includespods of rack computing systems arranged in one or more rows and columns.In some embodiments, elements of an air removal system may be sharedamong two or more pods in a data center.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

What is claimed is:
 1. A data center, comprising: a computing room; aplurality of computing devices in the computing room; an air handlingsystem configured to move air, wherein at least a portion of the airmoved by the air handling system flows across heat producing componentsin at least some of the computing devices in the computing room, the airhandling system comprising: a return duct configured to re-circulate aportion of heated air to a supply duct for the computing room, whereinthe heated air comprises air moved across the heat producing componentsof the computing devices; and an exhaust vent configured to direct aseparate portion of the heated air to an ambient environment outside thecomputing room; and a turbine system coupled to the exhaust vent of theair handling system, wherein the turbine system comprises a rotor,wherein the rotor of the turbine system is configured to rotate inresponse to the separate portion of the heated air moved by the airhandling system to the ambient environment via the exhaust vent, whereinthe turbine system is configurable to generate electricity from rotationof the rotor.
 2. The data center of claim 1, wherein the air handlingsystem further comprises: a damper coupled to the exhaust vent; and acontrol system configured to control an air flow through the turbinesystem based at least in part on adjusting the damper.
 3. The datacenter of claim 1, wherein the rotor of the turbine system is located inan air passage of the air handling system.
 4. The data center of claim1, further comprising: a control system configured to operate theturbine system; and one or more energy storage devices, wherein at leastone of the energy storage devices is configured to: store energygenerated by the turbine system; and supply electrical power to the oneor more components in the data center using the stored energy; whereinthe control system is configured to supply electrical power from theenergy storage devices based on one or more conditions in the datacenter.
 5. The data center of claim 4, wherein the energy storage deviceis configured to supply power to the air handling system.
 6. A system,comprising: one or more rooms; an air handling system configured to moveair through at least one of the one or more rooms, the air handlingsystem comprising: a supply duct configured to direct air across heatproducing components in the at least one of the one or more rooms; areturn duct configured to re-circulate a portion of heated air to thesupply duct, wherein the heated air comprises air moved across the heatproducing components; and an exhaust vent configured to direct aseparate portion of the heated air to an ambient environment external tothe at least one of the one or more rooms; and a turbine system coupledto the air handling system, wherein the turbine system comprises arotor, wherein the rotor of the turbine system is configured to rotatein response to the separate portion of the heated air moved by the airhandling system to the ambient environment via the exhaust vent, whereinthe turbine system is configurable to generate electricity from rotationof the rotor.
 7. The system of claim 6, further comprising one or moreenergy storage devices, wherein at least one of the energy storagedevices is configured to: store energy generated by the turbine system;and supply electrical power using the stored energy.
 8. The system ofclaim 6, wherein the air handling system further comprises: a dampercoupled to the exhaust vent; and a control system configured to controlan air flow through the turbine system based, at least in part, onadjusting the damper.
 9. The system of claim 6, wherein the rotor of theturbine system is located in an air passage of the air handling system.10. The system of claim 6, wherein the turbine system is locateddownstream from a damper coupled to the exhaust vent.
 11. The system ofclaim 6, wherein the exhaust vent comprises a section having a reducedcross sectional area, wherein the intake of the turbine is located inthe section having the reduced cross sectional area.
 12. The system ofclaim 6, wherein the turbine system further comprises a stator ring andthe rotor comprises a plurality of blades comprising one or moremagnetic elements, wherein rotation of the blades relative to the statorring induces electrical current.
 13. The system of claim 6, wherein theturbine system is configured to change an orientation of the rotorrelative to an air stream moving across the rotor.
 14. The system ofclaim 6, wherein the turbine system is configured to reposition therotor to rotate in a natural wind.
 15. The system of claim 6, furthercomprising a control system, wherein the control system is configured tooperate the turbine system to generate electricity or supply electricalpower in response to one or more conditions of the room or the airhandling system.
 16. The system of claim 6, wherein the supply duct, thereturn duct, or an other duct of the air handling system comprises avariable flow passage, wherein the variable flow passage is configurableto alter the flow through the rotor of the turbine system.
 17. A method,comprising: moving air through an enclosed space to control conditionsof the air in the enclosed space, wherein the enclosed space comprisesone or more heat producing components; moving at least a portion of theair via an air handling system, after passing the air over the one ormore heat producing components, in a return path; and moving a separateportion of the air, after passing the air over the one or more heatproducing components, to an ambient environment via a rotor of a turbinesystem such that the rotor of the turbine system rotates; and generatingelectrical power from rotation of the rotor.
 18. The method of claim 17,further comprising adjusting a damper to control an air flow of theseparate portion of the air.
 19. The method of claim 17, wherein therotor is located in a passage of an air handling system.
 20. The methodof claim 17, wherein generating electrical power from rotation of therotor comprises changing the orientation of the rotor relative to an airflow to promote rotation of the rotor.
 21. The method of claim 17,further comprising storing at least a portion of the electrical energygenerated from the turbine system.
 22. The method of claim 21, furthercomprising supplying electrical power from the stored electrical energyto a cooling system for the enclosed space.